1. Field of the Invention
This invention relates to an optical waveguide fabricated by flame hydrolysis deposition, and a method for fabricating the same. Specifically this invention relates to a method for forming a core or a cladding layer of phosphorus content glass film.
2. Related Background Art
Optical waveguides are expected to be one of prospective basic devices of optical systems. Various types of optical waveguides have been proposed, and one of them comprises a core formed mainly of quartz, and a cladding surrounding the core, whereby signal beams are confined in the core to be propagated therethrough. The optical waveguide of this type has the doped core, and the cladding by flame hydrolysis deposition. For example, a known flame hydrolysis deposition (Japanese Patent Laid-Open Publication No. 105111/1983) comprises depositing glass fine particles are deposited from a flame burner to form a porous glass fine particle layer, and heating and vitrifying the glass fine particle layer.